German prosecutors said today they have asked judges to fine three scientists at the prestigious Max Planck Institutes for animal cruelty over experiments on monkeys' brains.

Investigators in southwestern university town Tuebingen said the three men aged between 49 and 67 were accused of "ending experiments on three monkeys too late and thereby causing the animals' ongoing pain for a longer period."

In German law, animal cruelty can be punished with a sentence of up to three years in jail, depending on the seriousness of the crime.

This case deals with experiments by the Max Planck Institute for Biological Cybernetics that were approved by authorities -- on the condition that the monkeys be killed if signs of suffering became apparent.

"Against the specified conditions for ending the experiment, (the accused) delayed in euthanising the animals, thereby causing significant and longer-lasting harm to their well-being," the prosecutors said.

"The accused should have recognised their obligation to intervene," they added.

(PTI)